Several neuropsychiatric syndromes including Huntington's chorea, Altzheimer's disease, and Gilles de la Tourette's syndrome are being studied in terms of memory and intellectual function, neuroendocrine function, and possible pharmacological treatment. Huntington's patients are unable to utilize normally significant aids such as high verbal imagery to encode information deeply enough to allow consistent retrieval. A study of dopaminergic regulation of prolactin and growth hormone in Huntington's patients and normal controls indicates that there are deteriorated dopamine mediated control mechanisms for prolactin release in Huntington's chorea. Acute pharmacological testing with d-amphetamine, 1-amphetamine, and haloperidol in Gilles de la Tourette's syndrome suggests that the pathophysiology may be biochemically heterogeneous. Clozapine, a non-neuroleptic antipsychotic is being studied in Tourette's patients. Clinical trials of two psychotropic drugs known to stimulate appetite (lithium carbonate and delta-9-tetrahydrocannabinol) are underway in anorexia nervosa. Abnormalities in gastric function and cardiac rhythm have been documented in acute anorexia nervosa.